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Vulnerability record · public intelligence
CVE-2023-39240
HIGH

ASUS RT-AX55、RT-AX56U_V2 - Format String - 3

Published Sep 7, 2023 · Updated Nov 3, 2026

Severity · CVSSHIGH · Not scored
Known exploitationNot listed
EPSS / likelihood1.28%
QFinch risk scoreNot available

Original summary

Normalized public record · Updated Nov 3, 2026

ASUS RT-AX55、RT-AX56U_V2 - Format String - 3

Publisher and source text is retained separately from QFinch interpretation.

QFinch assessment

It is identified a format string vulnerability in ASUS RT-AX56U V2’s iperf client function API. This vulnerability is caused by lacking validation for a specific value within its set_iperf3_cli.cgi module. A remote attacker with administrator privilege can exploit this vulnerability to perform remote arbitrary code execution, arbitrary system operation or disrupt service.

Evidence: public source records

Affected products

Affected scope reported by the available public evidence
Affected package, product or rangeFix status
Consult the referenced vendor advisory for affected versions.Consult source advisory

Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.

Remediation

Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.

  1. Confirm the affected product and reachable code path exist in your environment.
  2. Apply the vendor-supported patch or mitigation from the primary advisory.
  3. Rescan the exact deployed revision and retain verification evidence.
Review primary references

Evidence coverage

FIRST-EPSSCVE-LIST-V5
SSVC priority
MEDIUM
Confidence
Not available
Aliases
None reported

Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.

Sources and record history

  1. www.twcert.org.tw ↗

Record history

Published Sep 7, 2023 · Last refreshed Nov 3, 2026